Abstract: The invention relates to a device and to a method for monitoring access to vessels during extracorporeal blood treatment. The invention forms a loop in the arterial and/or venous line and provides device for fixing a section of the line in a loop. When the line is stressed under tension, the loop contracts and the line finally kinks. The modification of the diameter of the line and the formation of a kink in the line leads to a rise of pressure in the line, which is monitored by a pressure monitoring device. If the pressure exceeds a predetermined threshold value, the aspirating cannula is in danger of slipping out of the vessel access or has partially or completely slipped out, thus allowing the threshold value to be determined for alarms.

Abstract: The present invention relates to a method and to a device for detecting the entry of air in a fluid system, in particular in an extracorporeal blood circuit of a blood treatment device comprising an arterial branch leading to the blood treatment unit and a venous branch leading from said blood treatment unit. Periodic fluctuations in the fluid system, in particular in the arterial tube, are measured upstream of the blood pump arranged in said arterial tube. The measured periodic pressure signal is analyzed spectrally in a system of functions, in particular a system of orthogonal functions, for example sine and cosine functions and the entry of air is deduced if at least one of the coefficients of the functions exceeds or falls below predefined threshold values.

Abstract: This invention relates to a method for clearing a wetted hydrophobic filter, in which in a first step the air permeability of the hydrophobic filter is monitored and in which in a second step the hydrophobic filter is cleared by means of a connected air pump, if it is detected that the hydrophobic filter is clogged. Furthermore, the invention relates to an apparatus for performing this method.

Abstract: The invention relates to a method and to a device for operating an electric peristaltic hose pump, in particular a hose pump for transporting fluids in medical-technical devices, in particular extracorporeal blood treatment devices. In order to monitor the regular operation of a hose pump, the power consumption of the pump or a physical variable in correlation with the power consumption, in particular the pump flow, is monitored. The pump flow includes a periodically non-altering direct component which is superimposed on a periodically altering alternating component. In order to monitor the regular operation of the hose pump, the alternating component of the power consumption in relation to the direct component of the power consumption is monitored as whether it increases and/or decreases during blood treatment.

Abstract: A method and device that identify impairments of the blood flow in an extra-corporeal blood circuit during extracorporeal treatment of the blood using an extracorporeal haemodialysis device, where the phase angle of at least one harmonic oscillation of an oscillating pressure signal that propagates in the extracorporeal blood circuit is determined. Impairments of the blood flow are detected in the extracorporeal blood circuit based on a characteristic modification of the phase angle of at least one harmonic oscillation of the pressure signal. A temporal modification of the phase angle may be compared with a predefined threshold value and an impairment is detected if the value of the modification of the phase angle is greater than the predefined threshold value. The method and device permit an early identification of a coagulation of the blood that flows through the haemodialysis unit, so that countermeasures can be initiated promptly.

Abstract: The invention relates to a process for monitoring the supply of substitution fluid upstream or downstream of a dialyser or filter arranged in an extracorporeal blood stream. One embodiment provides, for the detection of predilution or postdilution, for measuring the pressure in the blood stream downstream of the dialyser or filter, predilution or postdilution being recognized on the basis of the change in pressure following the shutting off and/or starting up of the substituate pump provided for conveying the substitution fluid. Another embodiment provides for recognizing predilution or postdilution on the basis of the comparison of the oscillating pressure signal attributable to the substituate pump to a characteristic reference signal. The characteristic reference signal to which the pressure signal of the substituate pump is compared is preferably the oscillating pressure signal of a blood pump arranged in the blood stream for conveying the blood upstream of the dialyser or filter.